Field of the Invention
The present invention relates to a piezoelectric ceramic with both the excellent piezoelectric constant and the excellent mechanical quality factor particularly at low temperature. The present invention moreover relates to a piezoelectric element, a multilayered piezoelectric element, a liquid discharge head, a liquid discharge device, an ultrasonic motor, an optical appliance, a vibration device, a dust removing device, an imaging device, an electronic appliance, or a piezoelectric device including the piezoelectric ceramic, and a manufacturing method for the piezoelectric ceramic.
Description of the Related Art
General piezoelectric ceramics are the ABO3 perovskite oxides such as lead zirconate titanate (hereinafter referred to as PZT). Since PZT contains lead as the A-site element, the influence on the environment has been concerned. In view of this, the piezoelectric ceramic including a perovskite oxide not containing lead has been suggested.
A known example of the perovskite type piezoelectric ceramic not containing lead is barium titanate. Japanese Patent No. 5344456 has disclosed the piezoelectric ceramic in which a part of the barium site of barium titanate is replaced by calcium and a part of the titanium site thereof is replaced by zirconium in order to improve the piezoelectric characteristics of barium titanate at around the room temperature. This piezoelectric ceramic, however, has the low mechanical quality factor and the low durability at high temperature, and is therefore unsuitable for the use in a resonant device.
Japanese Patent No. 5217997 has disclosed the piezoelectric ceramic in which a part of the barium site in barium titanate is replaced by calcium and manganese, iron, or copper is added. According to Japanese Patent No. 5217997, this ceramic has the excellent mechanical quality factor at around room temperature. At low temperature (0° C. or less), however, the mechanical quality factor is low and is therefore unsuitable for the use in a resonant device.
The present invention has been made in view of the above circumstances, and is to provide a piezoelectric ceramic having the excellent piezoelectric constant and mechanical quality factor particularly at low temperature by controlling the composition of the crystal grain boundary and the crystal structure.
The present invention moreover provides a piezoelectric element, a multilayered piezoelectric element, a liquid discharge head, a liquid discharge device, an ultrasonic motor, an optical appliance, a vibration device, a dust removing device, an imaging device, an electronic appliance, or a piezoelectric device including the piezoelectric ceramic, and a manufacturing method for the piezoelectric ceramic.